JPH1135867A - Aqueous ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ink composition capable of controlling the change in the luminous concentration of a coating film with time. SOLUTION: This aqueous ink composition comprises a coloring agent, a dispersant, a viscosity-controlling agent, water and an emulsion comprising an oil-soluble silicone. The emulsion comprising the oil-soluble silicone includes an emulsion containing at least one kind of silicone selected from dimethylsilicone, monomethylsilicone, phenylmethylsilicone, alkyl-modified silicones and amino-modified silicones. The oil-soluble silicone is contained in the emulsion in an amount of 0.01-10 wt.% based on the total amount of the ink composition. The coloring agent suitably includes inorganic pigments, organic pigments, direct dyes, and acidic dyes (especially titanium dioxide and zinc white). The coloring agent is used in an amount of 0.1-60 wt.% based on the total amount of the ink composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous ink composition, and more particularly to an ink composition useful as a recording ink such as a writing implement ink, a printing ink, and an ink jet ink. The present invention relates to an ink composition capable of suppressing the ink composition.

[0002]

2. Description of the Related Art Aqueous ink compositions are widely used in terms of safety and stability. For example, a water-based ink composition for a ball-point pen is formed by adding a water-soluble organic solvent to an aqueous solution containing a colorant (dye or pigment) as necessary, and a surfactant is used to improve lubricity. Is added.

[0003]

However, as described above, a water-soluble ink composition containing a surfactant is used to absorb water (such as water-based ink) on paper (eg, conventional copy paper). (Or a surface that can penetrate), the pigment (colorant) penetrates into the paper when it is applied (written), and over time (for example, immediately after writing and after a few minutes of writing), the paint or image is applied. The color density of the film (hereinafter, simply referred to as “coating film”) decreases. In addition, problems such as the bleeding of the coating film also occur.

[0004] An object of the present invention is to provide an aqueous ink composition which can suppress a decrease in the color density of a coating film. Another object of the present invention is to provide a water-based ink composition which can form a coating film with less bleeding, in addition to the above-mentioned properties.

[0005]

SUMMARY OF THE INVENTION The present invention has been intensively studied to solve these disadvantages, and as a result, contains an emulsion composed of a colorant, a dispersant, a viscosity modifier, water, and an oil-soluble silicone. It has been found that the use of such an aqueous ink composition makes it possible to suppress or prevent a decrease in the color density of a coating film and to form a coating film with less bleeding, thereby completing the present invention. The invention according to claim 1 includes a coloring agent,
An aqueous ink composition containing at least a dispersant, a viscosity adjusting agent and water contains an emulsion composed of an oil-soluble or water-insoluble (hereinafter, simply referred to as "oil-soluble") silicone. It is an aqueous ink composition characterized by the following.

Since the aqueous ink composition of the present invention contains an emulsion composed of an oil-soluble silicone, it is considered that a coloring agent (dye or pigment) hardly permeates into the paper. This is because the oil-soluble silicone forms an oil film on the absorption surface with the penetration of water into the paper, thereby suppressing or preventing the penetration of the colorant into the absorption surface (paper interior). Seem. Accordingly, it seems that bleeding of the ink can be suppressed or prevented even on the absorption surface (on the paper surface). Therefore, it is possible to form a coating film with little decrease in color density and to form a coating film with little bleeding. The present invention is an aqueous ink composition that utilizes such properties of an emulsion composed of an oil-soluble silicone.

[0007] The emulsion composed of an oil-soluble silicone (hereinafter sometimes simply referred to as "silicone emulsion") is selected from, for example, dimethyl silicone, monomethyl silicone, phenylmethyl silicone, alkyl-modified silicone and amino-modified silicone. An emulsion containing at least one oil-soluble silicone prepared as described above can be used. The amount of the silicone emulsion to be used is from 0.01 to the total amount of the ink composition.
10% by weight. The invention according to claim 2 is the aqueous ink composition according to claim 1, wherein an emulsion containing at least one selected from dimethyl silicone, monomethyl silicone, phenylmethyl silicone, alkyl-modified silicone, and amino-modified silicone is used as the silicone emulsion. is there. The invention according to claim 3 is the emulsion according to claim 1 or 2, wherein the content of the oil-soluble silicone is 0.01 to 10% by weight based on the total amount of the ink composition. It is an aqueous ink composition.

The colorant includes, for example, at least one colorant selected from inorganic pigments, organic pigments, direct dyes and acid dyes, and may be of any color. In particular, when a white colorant (for example, a white inorganic pigment such as titanium oxide or zinc white) is used as a colorant,
In some cases, the effects of the present invention can be significantly exhibited. The amount of the colorant used is 0.1 to 60% by weight based on the total amount of the ink composition. The invention according to claim 4 is the aqueous ink composition according to any one of claims 1 to 3, wherein the colorant is at least one selected from inorganic pigments, organic pigments, direct dyes, and acid dyes. The invention of claim 5 is the aqueous ink composition according to any one of claims 1 to 3, wherein the colorant is titanium oxide or zinc white. The invention according to claim 6 is the aqueous ink composition according to any one of claims 1 to 5, wherein the content of the colorant is 0.1 to 60% by weight based on the total amount of the ink composition.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(Silicone Emulsion) A feature of the aqueous ink composition of the present invention resides in that it contains an emulsion composed of an oil-soluble silicone. Therefore, it seems that the colorant (pigment or dye) in the ink can be prevented from penetrating into the inside of the absorbing surface of the conventional paper (for example, copy paper or colored paper). Therefore, the coating has a high coloring density. In addition, bleeding of the ink can be suppressed even on the paper surface.

As the oil-soluble silicone in the silicone emulsion, any water-insoluble or oil-based silicone resin can be used without particular limitation. Examples of such an oil-soluble silicone include dimethyl silicone, monomethyl silicone, phenylmethyl silicone, alkyl-modified silicone, and amino-modified silicone. Preferred oil-soluble silicones include dimethyl silicone, monomethyl silicone, phenylmethyl silicone, alkyl-modified silicone and the like. The oil-soluble silicones can be used alone or in combination of two or more.

The molecular weight and viscosity of the oil-soluble silicone are not particularly limited. The viscosity of the oil-soluble silicone is, for example, 25
At 100 to 100,000 cps (for example,
(200 to 50,000 cps).
Preferred oil-soluble silicones have a viscosity of 10,000 cp.
s or less (for example, 200 to 10,000 cps).

The silicone emulsion may be a self-emulsifying emulsion or a forced emulsifying emulsion using a surfactant (mechanical emulsifying emulsion). In addition, in the forced emulsification type emulsion, the viscosity (25 ° C.) is usually 10,000 cps or less (for example, 20 cps).
In many cases, a silicone having a low polymerization degree of about 0 to 10,000 cps) is used.

The silicone emulsion can be prepared, for example, by mixing an oil-soluble silicone, water and, if necessary, a surfactant. For example, adding a predetermined amount of a surfactant to water,
Further, it can be prepared by adding a predetermined amount of the oil-soluble silicone while stirring. Any surfactant can be used from anionic, cationic, nonionic and amphoteric surfactants.

Although the concentration of the oil-soluble silicone in the silicone emulsion is not particularly limited, it is usually 25 to 25.
It is often about 50% by weight, preferably 30 to 4%.
0% by weight.

More specifically, as the silicone emulsion used in the present invention, for example, SH7036 and SH87, trade names, manufactured by Toray Dow Corning Silicone Co., Ltd.
10, SH8701, SH8705, SH872
2, SH8707, SH8702, SH870
9, BY22-819, SH8627, BY22
-826, BY22-839, BY22-830,
BY22-835, BY22-840, SH70
24, SH7025, SH7028A, SM70
60, SM7001, SH490, SM870
1, SM8706, SM7706, SH550
3, SH5510, SM5513, SH556
1, SH5507, SM5514, SH873
0, SH5501, SH5505, SM551
1, SM5512, SM5515, SM551
7, BY22-517, SM5571, SM55
Commercial products such as 72F, SM5573, and BY22-526 can be used.

The silicone emulsions can be used alone or in combination of two or more. In the silicone emulsion, the amount of the oil-soluble silicone used is, for example, 0.01 to 10% by weight based on the total amount of the ink composition.
Preferably it is 0.5 to 5% by weight. If the amount of the oil-soluble silicone is too small, it is difficult to suppress the penetration of the ink into the coated surface (absorbing surface such as paper), and the color density of the coating film is reduced. On the other hand, if the amount is too large, the coating film bleeds and the coating film formability (printing formability) decreases.

(Colorant) As the colorant contained in the aqueous ink composition of the present invention, various known colorants can be used.
Examples of the coloring agent include inorganic pigments (for example, titanium oxide, iron oxide, carbon black, etc.) and organic pigments (for example, azo pigments, condensed polyazo pigments, phthalocyanine pigments, quinacridone pigments, anthraquinone pigments) Pigments,
Dioxazine-based pigments, indigo-based pigments, thioindigo-based pigments, perinone-based pigments, perylene-based pigments, melamine-based pigments, etc.), resin colored bodies, dyes, and the like. The colorants can be used alone or in combination of two or more.

More specifically, as the inorganic pigment in the colorant, for example, in addition to white inorganic pigments such as titanium oxide and zinc white, carbon black (eg, furnace black, contact black, thermal black, acetylene black) , Black iron oxide, yellow iron oxide, red iron oxide, ultramarine, navy blue, cobalt blue, titanium yellow, turquoise, molybdenum orange, and the like.

The organic pigments include, for example, white organic pigments such as ethylenebismelamine and C.I. I. Pigmen
T RED2, 3, 3, 5, 17, 22, 38
Same 41, Same 48: 2, Same 48: 3, Same 49, Same 50:
1, 53: 1, 57: 1, 58: 2, 60, 63: 1, 63: 2, 64: 1, 88, 11
2, 122, 123, 144, 146, 14
9, 166, 168, 170, 176, 17
7, 178, 179, 180, 185, 19
0, 194, 206, 207, 209, 21
6, 245; C.I. I. PIGMENT ORANGE
5, 10, 13, 16, 16, 36, 40, 4
3; I. PIGMENT VIOLET 19, 2
3, 3, 31, 33, 36, 38, 50; C.I.
I. PIGMENT BLUE2, 15 and 15:
1, 15: 2, 15: 3, 15: 4, 15:
5, 16, 17, 22, 25, 60, 6
6; I. PIGMENT BROWN 25, 2
6; I. PIGMENT YELLOW 1 and 3,
12, 12, 13, 81, 93, 94, 95, 97, 99, 108, 109, and 11
0, 117, 120, 139, 153, 16
6, 167 and 173; I. PIGMENT G
REEN7, 10, and 36.

For example, styrene resin,
Dyeing (e.g., a basic dye or a fluorescent basic dye) and / or a fluorescent whitening agent onto an aqueous dispersion obtained by emulsion polymerization using an acrylic resin or an acrylonitrile resin alone or using two or more types ( (Colored) colored resin emulsion. The average particle size of the polymer particles in the aqueous dispersion is not particularly limited, for example, 0.1 to 1 μm
It is about. The resin colored body may be a resin in which a dye (for example, a fluorescent dye) is dissolved.

The form of the pigment may be a resin ball, a metal powder, or the like.

Examples of the dye include direct dyes (for example, CI Direct Black 17, 19, and 2).
2, 32, 38, 51, 71; I. Direct yellow 4, ditto 26, ditto 44, ditto 50; I. Direct Red 1, 4, 23, 31, 37, 39, 75, 80, 81, 83, 225, 226, 227; I. Direct Blue 1 and 1
5, 41, 71, 86, 87, 106, 1
08, 199, etc.), acid dyes (for example, CI Acid Black 1, 2, 24, 26, 31, 52, 107, 109, 110, 119, 1)
54; I. Acid Yellow 1, 7, 17, 19, 23, 25, 29, 38, 42, and 4
9, 61, 72, 78, 110, 127, 135, 141, 142; I. Acid Red 8, 9, 14, 18, 26, 27, 35
37, 51, 52, 57, 82, 83, 87, 92, 94, 111, 129, 13
1, 138, 186, 249, 254, 26
5, 276; I. Acid Violet 15, 17, 17, 49; C.I. I. Acid Blue 1, 7, 9, 9, 15, 22, 23, 25, 40, 4
1, 43, 62, 78, 83, 90, 9
3, 100, 103, 104, 112, 11
3, 158; C.I. I. Acid Green 3, 9, 16, 25, 27; C.I. I. Acid orange 56
), Food dyes (for example, CI Food Yellow 3 and the like), and macalite green (CI.
0), Victoria Blue FB (CI.44045),
Methyl violet FN (CI. 42535), rhodamine F4G (CI. 45160), rhodamine 6G
CP (CI. 45160) and the like can be exemplified.

Preferred coloring agents include inorganic pigments, organic pigments, direct dyes, and acid dyes (more preferably, white inorganic pigments such as titanium oxide and zinc white). As the colorant, a white inorganic pigment (particularly titanium oxide) can be suitably used, but pigments and dyes of other colors can be used without any problem. The amount of the colorant (pigment, dye) used can be selected according to the type and specific gravity of the colorant, for example,
0.1 to 60% by weight based on the total amount of the ink composition can be used. For example, when titanium oxide is used as the colorant, a preferable amount of the colorant is 1 to the total amount of the ink composition.
It is about 0 to 45% by weight. If the amount of the coloring agent is too small, the coloring density of the coating film is low. On the other hand, if it is too large, the viscosity becomes high and the writability deteriorates.

(Dispersant) As the dispersant, commonly used water-soluble resins, resin emulsions, surfactants and the like can be used. The water-soluble resin may be any of a natural product, a semi-synthetic product, and a synthetic product, but the synthetic product is most suitable in view of the problem of mold and spoilage and the viscosity characteristics as an ink (for example, ink for writing implements). Examples of these synthetic products include a water-soluble acrylic resin, a water-soluble maleic resin, a water-soluble styrene resin, a water-soluble styrene-acrylic resin, a water-soluble styrene-maleic resin, polyvinylpyrrolidone,
Examples include polyvinyl alcohol, water-soluble ester-acrylic resin, and water-soluble urethane resin. Examples of the resin emulsion include an acrylic emulsion, a vinyl acetate emulsion, a urethane emulsion, and a styrene-butadiene emulsion. As the surfactant, any one of anionic, cationic, nonionic and amphoteric surfactants can be used. The dispersants can be used alone or in combination of two or more.

The amount of the dispersant used is 1 to 20% by weight, preferably 3 to 15% by weight, based on the total amount of the ink composition. If the amount of the dispersant is too small, the dispersion stabilizer is low,
On the other hand, if it is too large, the viscosity becomes high and the writability decreases.

(Viscosity adjuster) As the viscosity adjuster, a conventional viscosity adjuster, for example, a water-soluble polymer can be used. Among them, natural polysaccharide, semi-synthetic cellulose-based polymer, water-soluble synthetic polymer Molecules can be suitably used. The viscosity modifiers can be used alone or in combination of two or more.

Examples of natural polysaccharides include polymers having a high molecular chemical structure composed of monosaccharides such as glucose, galactose, rhamnose, mannose and glucuronate. More specifically, natural polysaccharides include, for example, guar gum, xanthan gum, welan gum, ramzan gum, locust bean gum, pullulan, succinoglucan or derivatives thereof, trigant gum, tarara gum, karaya gum, gaddy gum, arabic Nogalactan gum, quince seed gum, silium seed gum, gum arabic, pectin, starch and the like. Examples of semi-synthetic cellulose-based polymers include methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose,
Examples include hydroxypropylethylcellulose, carboxymethylcellulose or a salt thereof (such as a sodium salt). The water-soluble synthetic polymer includes, for example, polyvinyl pyrrolidone, polyethylene oxide, polyacrylic acid, methyl vinyl ether maleic anhydride copolymer, and the like.

The viscosity modifier is added to adjust the viscosity of the ink composition to a desired viscosity, and the amount of the viscosity modifier is not particularly limited. Therefore, the amount of the viscosity modifier used can be selected according to the type and amount of the colorant, dispersant, water, and silicone emulsion. When the water-soluble ink composition of the present invention is used as an ink composition for a ballpoint pen, the viscosity of the ink composition (at 25 ° C.)
From the viewpoint of ink dispersibility and writability, 200 to 10,000
It is preferably about cps. In consideration of this and the amounts of other components used, the amount of the viscosity modifier used in the ink composition for ballpoint pens is, for example, 0.1 to 10% by weight, preferably 0.2 to 10% by weight based on the total amount of the ink composition. Often it is 5% by weight.

As the (water) water, conventional water (for example, ion-exchanged water, tap water, industrial water, groundwater, well water, etc.)
It can be used without any problems. The amount of water used is not particularly limited, and can be selected according to the type and amount of other components (colorant, dispersant, silicone emulsion, etc.) and the viscosity of the intended ink composition. . The amount of water used can be selected from a wide range, for example, from about 1 to 80% by weight based on the total amount of the ink composition. The preferred amount of water to be used is about 20 to 70% by weight (for example, 30 to 60% by weight).

The ink composition of the present invention may contain, if necessary, a wetting agent, a surfactant, an antifoaming agent, a leveling agent, a coagulation inhibitor, a pH adjuster, a pseudoplasticity-imparting agent, a rust inhibitor, an antiseptic and a mold. Conventional additives such as agents may be added. Examples of the wetting agent include propylene glycol, ethylene glycol, diethylene glycol, glycerin and the like. As the surfactant, a conventional surfactant (for example, polyoxyethylene alkyl ether phosphate, etc.) can be used. Note that the surfactant can also function as a lubricant. Further, it may contain a solvent such as a water-soluble organic solvent.

(Production method) The aqueous ink composition of the present invention can be prepared by mixing the above components, a colorant, a dispersant, a viscosity modifier, water and a silicone emulsion. For example,
It can be prepared by adding a predetermined amount of a colorant, a dispersant, a viscosity adjusting agent, a silicone emulsion, and, if necessary, a lubricant, a surfactant and an additive to a predetermined amount of water, and stirring the mixture.
In a preferred preparation method, a colorant, a dispersant, and a lubricant, if necessary, are added to a predetermined amount of water to prepare a dispersion of the colorant in advance, and the dispersion of the colorant and a viscosity modifier , A silicone emulsion, the balance of water, and other components (such as surfactants and additives).

The aqueous ink composition of the present invention has a small change over time in the decrease in the color density of the coating film and has little bleeding, and therefore, has a good effect on recording inks (eg, printing inks, writing implement inks, ink jet recording inks). And so on). In particular, the aqueous ink composition of the present invention is useful as an ink for writing implements, especially an aqueous ballpoint pen ink (gel type ink). The color of the coating (for example, red,
Color, such as blue, yellow, green, and purple), and a decrease in the color density of the coating film can be suppressed. In particular, even if the color of the coating film is white, coating (writing, printing) on a black paper such as black paper can form a coating film with a suppressed reduction in color density. In addition, bleeding and the like can be suppressed, and a clear print or image coating film can be formed. Therefore, when the aqueous ink composition of the present invention is used, as the paper used for the coated surface, a commonly used paper such as a conventional copy paper or a conventional colored paper (a water-insoluble resin or the like on the paper surface, Even paper that has not been specially processed) can be used without any problems.

[0033]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. (Preparation of Colorant Dispersion) The following titanium oxide was used as a colorant and mixed with a dispersant (styrene-acrylic resin) or the like to prepare a titanium oxide dispersion having the following composition. This titanium oxide dispersion was used in Examples 1 to 20 below. -Titanium oxide 50 parts by weight (trade name: Kronos-KR270, manufactured by Titanium Industry Co., Ltd.)-Styrene-acrylic resin 5 parts by weight-Propylene glycol 10 parts by weight-Ion exchange water 35 parts by weight

Example 1 50 parts by weight of the titanium oxide dispersion, 0.32 parts by weight of xanthan gum, 5 parts by weight of glycerin, 28.25 parts by weight of polyoxyethylene alkyl ether phosphate, 28.25 parts by weight of ion-exchanged water And 1.43 parts by weight of a silicone emulsion (trade name: SH7024, manufactured by Dow Corning Toray Silicone Co., Ltd.) to prepare an ink composition. (Example 2) 26.82 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (trade name: SH7024, manufactured by Dow Corning Toray Silicone Co., Ltd.) was used. , 2.8
An ink composition was prepared in the same manner as in Example 1 except that 6 parts by weight was used. Example 3 25.39 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. , 4.2
An ink composition was prepared in the same manner as in Example 1 except that 9 parts by weight was used. Example 4 23.96 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. , 5.7
An ink composition was prepared in the same manner as in Example 1 except that 2 parts by weight was used. Example 5 22.53 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (trade name: SH7024, manufactured by Dow Corning Toray Silicone Co., Ltd.) was used. , 7.1
An ink composition was prepared in the same manner as in Example 1 except that 5 parts by weight was used.

Example 6 28.36 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone, trade name: SH7024) was used. Instead to,
An ink composition was prepared in the same manner as in Example 1 except that 1.32 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH490) was used. (Example 7) 27.04 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
(Product name: SH490) An ink composition was prepared in the same manner as in Example 1 except that 2.64 parts by weight was used. Example 8 25.72 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
(Product name: SH490) An ink composition was prepared in the same manner as in Example 1 except that 3.96 parts by weight was used. (Example 9) In addition to using 28.25 parts by weight of ion-exchanged water, 24.4 parts by weight was used, and a silicone emulsion (trade name, manufactured by Dow Corning Toray Silicone Co., Ltd., trade name:
Example 1 except for using 5.28 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone, trade name: SH490) instead of 1.43 parts by weight of SH7024).
In the same manner as in the above, an ink composition was prepared. (Example 10) 23.08 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
(Product name: SH490) An ink composition was prepared in the same manner as in Example 1 except that 6.6 parts by weight was used.

(Example 11) 28.25 ion-exchanged water was used.
28.36 parts by weight instead of parts by weight and silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) instead of 1.43 parts by weight of silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd.) : SH7036) An ink composition was prepared in the same manner as in Example 1, except that 1.32 parts by weight was used. (Example 12) 27.04 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
(Trade name: SH7036) An ink composition was prepared in the same manner as in Example 1 except that 2.64 parts by weight was used. Example 13 25.72 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
(Product name: SH7036) An ink composition was prepared in the same manner as in Example 1 except that 3.96 parts by weight was used. Example 14 In place of using 28.25 parts by weight of ion-exchanged water, 24.4 parts by weight was used, and a silicone emulsion (trade name, manufactured by Toray Dow Corning Silicone Co., Ltd., trade name:
An ink composition was prepared in the same manner as in Example 1, except that instead of 1.43 parts by weight of SH7024), 5.28 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7036) was used. (Example 15) 23.08 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
(Trade name: SH7036) An ink composition was prepared in the same manner as in Example 1 except that 6.6 parts by weight was used.

Comparative Example 1 29.18 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone, trade name: SH7024) was used. Instead to,
Silicone emulsion (manufactured by Toray Dow Corning Silicone, trade name: SH3746; water-soluble silicone)
An ink composition was prepared in the same manner as in Example 1 except that 0.5 part by weight was used. (Comparative Example 2) 28.68 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
An ink composition was prepared in the same manner as in Example 1 except that 1 part by weight of trade name: SH3746; water-soluble silicone) was used. (Comparative Example 3) 28.18 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
Trade name: SH3746; water-soluble silicone) An ink composition was prepared in the same manner as in Example 1, except that 1.5 parts by weight were used. (Comparative Example 4) 27.68 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
An ink composition was prepared in the same manner as in Example 1 except that 2 parts by weight of trade name: SH3746; water-soluble silicone) was used. (Comparative Example 5) 27.18 parts by weight of ion-exchanged water was used instead of 28.25 parts by weight, and 1.43 parts by weight of a silicone emulsion (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH7024) was used. Silicone emulsion (Toray Dow Corning Silicone,
Trade name: SH3746; water-soluble silicone) An ink composition was prepared in the same manner as in Example 1, except that 2.5 parts by weight were used.

Using the ink compositions of Examples 1 to 15 and Comparative Examples 1 to 5 as ink for a ballpoint pen, writing was performed on a conventional black colored paper, and the reflectance (%) of the coating film (image) after 60 minutes of writing was calculated. ) Was measured. The result is shown in FIG. FIG.
In the above, □ corresponds to an ink composition using SH7024 as a silicone emulsion, ○ corresponds to an ink composition using SH490 as a silicone emulsion, and Δ corresponds to a product name as a silicone emulsion. : Corresponds to an ink composition using SH7036, and x corresponds to an ink composition using SH3746 (water-soluble silicone) as a silicone emulsion. The reflectance (%) can be measured using a Sakura densitometer model PDA-65 (manufactured by Konishi Roku Photo Industry Co., Ltd.) using an amber filter.

As is apparent from the graph of FIG. 1, the ink compositions of the examples have excellent image reflectance after 60 minutes of writing. That is, the ink compositions of Examples have a high coloring density of the coating film after writing, and can prevent or suppress a decrease in the coloring density of the coating film. In particular, an emulsion composed of a low-polymerization degree silicone having a viscosity of 10,000 cps or less (SH7024 (trade name) used in Examples 1 to 5 and Examples 11 to 1)
No. 5 (SH7036, especially SH7036, manufactured by Toray Dow Corning Silicone Co., Ltd.) has excellent color density of the coating film. On the other hand, in the ink composition of the comparative example, the color density of the coating film is low (lower than that of the silicone-free ink), and the colorant seems to permeate into the paper. This is probably because the water-soluble silicone reduces the surface tension of the ink. Therefore, the ink compositions of the examples can suppress the colorant in the ink from penetrating into the paper. Further, in the examples, the coating film had little bleeding and was clear.

[0040]

The aqueous ink composition of the present invention comprises a coloring agent,
Since it contains a viscosity adjusting agent, a dispersant, water and a silicone emulsion, a coating film having a high coloring density can be formed.
Also, the sharpness of the coating film is excellent.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the modified silicone content and the reflectance of a coating film.

Claims (6)

[Claims] 1. An aqueous ink composition comprising an emulsion composed of an oil-soluble silicone in an aqueous ink composition containing at least a colorant, a dispersant, a viscosity modifier and water. . 2. The aqueous solution according to claim 1, wherein the emulsion composed of an oil-soluble silicone is an emulsion containing at least one selected from dimethyl silicone, monomethyl silicone, phenylmethyl silicone, alkyl-modified silicone, and amino-modified silicone. Ink composition. 3. The aqueous ink composition according to claim 1, wherein the content of the oil-soluble silicone in the emulsion comprising the oil-soluble silicone is 0.01 to 10% by weight based on the total amount of the ink composition. . 4. The aqueous ink composition according to claim 1, wherein the colorant is at least one selected from inorganic pigments, organic pigments, direct dyes and acid dyes. 5. The aqueous ink composition according to claim 1, wherein the colorant is titanium oxide or zinc white. 6. The aqueous ink composition according to claim 1, wherein the content of the colorant is 0.1 to 60% by weight based on the total weight of the ink composition.