JP3348181B2 - Aqueous ink composition for ballpoint pens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition for a ballpoint pen, which contains at least a coloring material, water and a thickening resin .

[0002]

2. Description of the Related Art In general, ink compositions for writing instruments use dyes and / or pigments as coloring materials, dissolve and / or disperse these coloring materials in a solvent, and adjust or fix viscosity as necessary. A water-soluble polymer or resin is added to improve the solubility, a surfactant is added to improve the solubility or dispersion stability, and an antiseptic / antifungal agent is added. Here, the viscosity of the ink composition is regarded as important because it is closely related to the form of the writing instrument.

[0003] In the case of low-viscosity ink, it is difficult to stably supply ink to the pen tip unless a special ink supply mechanism such as a valve structure is employed. ing. In such a writing instrument, the remaining amount of the ink is difficult to understand in appearance. On the other hand, since the ink having a certain high viscosity can be held in a raw ink state in a pipe body or the like, the ink can be stored in a transparent or translucent hollow container so that the remaining ink amount can be determined.

In the above-described raw ink type ballpoint pen, the viscosity of the ink composition is generally adjusted by adding a water-soluble polymer. In the case of an aqueous ink composition containing water in the solvent of the ink composition, for example, natural gum arabic, tragacanth gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, xanthen gum, dextran, semi-synthetic Methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium starch glycolate, sodium alginate, propylene glycol alginate, synthetic polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, vinyl acetate And a water-soluble polymer such as a copolymer of polyvinylpyrrolidone and an alkali metal salt of an acrylic resin. It has been used as a mixture of seeds or more.

[0005]

The ballpoint pen rotates an ink-adhered ball on a writing surface such as paper and transfers the ink adhering to the ball to the writing surface. Not only does the viscosity become too high, causing the ball to hinder smooth rotation, but also increases the resistance of the ink when it passes through the ink passage of the pen tip, reducing the amount of ink supplied to the ball and resulting in uneven writing lines. . In the case where such a situation is serious, a phenomenon occurs that writing cannot be performed at all. In particular, in the case of an ink thickened with a water-soluble polymer, when the solvent in the ink evaporates, the viscosity increases significantly because the ratio of the thickener increases. Since the amount of ink around the ball and in the ball holding chamber is extremely small, the viscosity of the ink rises greatly at the pen tip just by evaporating a little water in the ink, and handwriting is liable to be blurred. there were. In particular, when a pigment is used as a coloring material, the pigment agglomerates due to evaporation of the solvent, which sometimes makes permanent writing impossible. Conventionally, in order to prevent ink drying, it is common to increase the amount of a high-boiling solvent to be added, but this does not completely prevent drying of the pen tip, and also causes the handwriting to be easily oozed due to slow drying of the handwriting. There was also a problem.

[0006]

That is, the present invention provides a ballpoint pen comprising at least a coloring material, water, and a thickening resin.
In the aqueous ink composition for, the resin for thickening, the following
A compound represented by the general formula (Formula 2) and / or a salt thereof
Yes, further contains sugar alcohol, viscosity of ink composition
The gist of the present invention is a water-based ink composition for a ball-point pen having a water content of 50 cp or more and 2000 cp or less .

[0007]

Embedded image

When the water-based ink composition of the present invention is used as an ink composition for water-based ballpoint pens, the ink viscosity should be 50 to 2000 cp (less than 600 cp using a standard cone rotor 1 rpm of an ELD type viscometer manufactured by Tokimec Co., Ltd.). Measurement: 600 cp or more, measured by Tokimec ELD viscometer ST rotor 20 rpm, temperature 25
Set in the range of ℃). When the ink viscosity is less than 50 cp, it becomes difficult to hold the ink in the hollow cylinder,
If it is higher than cp, the ink ejection amount decreases and the handwriting becomes light in density.

In the aqueous ink composition of the present invention, as a coloring agent, any of the dyes and pigments conventionally used in aqueous ink compositions can be used without any limitation. . I. Direct Black 17,
19, 22, 22, 32, 51, 71,
C. I. Direct Yellow 4, 26, 44, 5
0,. Direct Red 1, Same 4, Same 23, Same 31, Same 37, Same 39, Same 75, Same 80, Same 81, Same 83, Same 2
25, 226, 227, C.I. I. Direct Blue 1, 15, 15, 41, 86, 87, 10
6, 108 and 199), C.I. I.
Acid Black 1, 2, 24, 26, 31,
52, 107, 109, 110, 119, 154, C.I. I. Acid Yellow 1, 7, 17, 19, 23, 25, 29, 38, 42, 4
9, 61, 72, 78, 110, 127, 135, 141, 142, C.I. 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, C.I. 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
Acid dyes such as C.I. I. Food dyes such as Food Yellow 3, Malachite Green (CI.42000), Victoria Blue FB (CI.44045), Methyl Violet FN (CI.42535), Rhodamine F4
G (CI. 45160), Rhodamine 6 GCP (C.I.
I. 45160).

The pigment is used as a coloring material of the ink. For example, carbon black such as furnace black, contact black, thermal black, and acetylene black, black iron oxide, yellow iron oxide, red iron oxide, and ultramarine , Navy blue, cobalt blue, titanium yellow,
Inorganic pigments such as turquoise and molybdate orange;
I. PIGMENT RED 2, 3, 5, 5
7, 22: 38, 41: 48: 2, 48:
3, 49, 50: 1, 53: 1, 57: 1, 58: 2, 60, 63: 1, 63: 2, 64:
1, 88, 112, 122, 123, 14
4, 146, 149, 166, 168, 17
0, 176, 178, 179, 180, 18
5, 245, 146, 170, 176, 17
7, 185, 190, 194, 206, 20
7, 209, 216, 245, C.I. I. PIGM
ENT ORANGE 5, 10, 13, 16,
36, 40, 43, C.I. I. PIGMENT V
IOLET 19, 23, 31, 33, 36,
38, 50, C.I. I. PIGMENT BLUE
2, same 15, same 15: 1, same 15: 2, same 15: 3, same 15: 4, same 15: 5, same 16, same 17, same 22, same 2
5, 60, 66, C.I. I. PIGMENT BRO
WN 25, 26, C.I. I. PIGMENT YEL
LOW 1, 3, 12, 13, 24, 81
93, 94, 95, 97, 99, 108,
109, 110, 117, 120, 139,
153, 166, 167, 173, C.I. I. P
Organic pigments such as IGMENT GREEN 7, 10 and 36, 9.10-dianilino anthracene, a fluorescent dye dissolved in a synthetic resin, a synthetic resin colored with a fluorescent dye, and metal powder.

Further, in the case of a pigment ink composition, an aqueous ink composition base in which a pigment is dispersed in an aqueous medium can be used. Specifically, Fuji. S
P series, Sanyo Dyeing Co., Ltd. Emacol series,
Sandye series, M, manufactured by Orient Chemical Industry Co., Ltd.
microPigmo series, MicroJet series, and Ryo. Fast series, NKW series manufactured by Nippon Fluorescent Chemicals, Toyo Soda Co., Ltd.
Cosmo Color series manufactured by Shinloych Co., Ltd., and Color Base Series manufactured by Shinloych Co., Ltd. are included. These can be used alone or in combination of two or more. Further, dyes, pigments, and dispersed pigments can be used in combination.

As the solvent, water is essential, and in addition, various organic solvents can be used. As the organic solvent, specifically, ethanol, methanol, 1-propanol,
2-propanol, 1,3-propanediol, 2-methyl-2,4-pentanediol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-phenoxyethanol, 2-benzyloxyethanol, (2-methoxyethoxy) ethanol,
2- (2-ethoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethanol
Butoxyethoxy) water-soluble organic solvents such as ethanol, glycerin, ethylene glycol, propylene glycol, diethylene glycol and polyethylene glycol.

As the thickening resin of the ink composition, a substance represented by the above general formula (Chemical Formula 2) and / or a salt thereof can be used, and one kind or a mixture of two or more kinds can be used.

As the sugar alcohol, tetrit, penchit, xylit, hexit, inositol, maltitol, maltotritol, maltotetratol, maltopentitol, maltohexitol, maltoheptitol, etc. can be used, and one or more kinds thereof can be used. Can be mixed and used.

The ink composition of the present invention is obtained by mixing a colorant, which is an essential component, water, a substance represented by the above general formula (2) and / or a salt thereof, and a sugar alcohol, and stirring the mixture. Obtainable. Further, if necessary, a coloring machine may be used, and the coloring material may be classified by filtration, centrifugation or the like.

In addition to the above essential components, various polymer dispersants, surfactants and water-soluble polymers can be used. For example,
As a polymer dispersant, natural gums such as gum arabic and tragacanth, glucosides such as saponin, lignin sulfonates, natural polymers such as shellac, polyacrylates, salts of styrene-acrylic acid copolymers, styrene -Maleic acid copolymer salts, vinyl naphthalene-maleic acid copolymer salts, β-naphthalene sulfonic acid formalin condensate salts, phosphates, and other anionic polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyethylene. Examples include nonionic polymers such as glycol. Examples of the surfactant include anionic surfactants such as fatty acid salts, higher alcohol sulfates, liquid fatty acid sulfates, and alkyl allyl sulfonates, polyoxyethylene alkyl ethers, sorbitan alkyl esters, and polyoxyethylene. Nonionic surfactants such as sorbitan alkyl esters are included. Examples of the water-soluble polymer include natural gum arabic, tragacanth gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, xanthen gum, dextran, semi-synthetic methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, Sodium starch glycolate, sodium alginate, propylene glycol alginate, synthetic polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, copolymer of vinyl acetate and polyvinyl pyrrolidone, acrylic resin And the like.

Further, in order to prevent the ink passage of the writing instrument from being clogged with mold and obstructing the outflow of the ink composition, sodium dehydroacetate, 1,2-benzoisothiazolin-3-one, sodium benzoate, morpholine, morpholine Preservatives and fungicides such as derivatives can also be added as appropriate.

Furthermore, in the case of a writing implement in which a metal is used in a portion that comes into contact with the ink composition, an anticorrosive such as benzotriazole or ethylenediaminetetraacetate may be appropriately added to prevent corrosion of the metal. it can.

Various known pH adjusters such as sodium hydroxide and triethanolamine may be added to the ink composition of the present invention. In particular, when the pH of the ink is in the range of 5.5 to 9, The stability over time of the viscosity is further improved.

[0020]

The reason why the aqueous ink composition for ball-point pens of the present invention hardly dries even at the pen tip portion and does not easily cause blurring even when the pen tip portion is exposed is considered as follows.

The substance represented by the general formula (Formula 2) forms a microgel structure in the ink and increases the viscosity of the ink. However, when the solvent in the ink evaporates, the density of the microgel increases, and the microgels are connected to each other. Form a film. Since this film is porous, the function of suppressing evaporation of the solvent is relatively weak, and the ink at the pen tip dries.
However, when the sugar alcohol is present in the ink, the sugar alcohol is taken into the film formed by the substance represented by the general formula (Formula 2), and is formed as a hygroscopic film. For this reason, the ink at the pen tip becomes difficult to dry. Also,
Since the formed film is brittle, it is easily broken by the force at the time of writing, so that a handwriting that is ejected immediately after writing and has no blurring can be obtained.

[0022]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples. In Examples and Comparative Examples, "parts" means "parts by weight".
Is shown.

The conditions for measuring the viscosity of each ink composition are 50
The value of less than cp is measured with a standard cone rotor 10 rpm of ELD type viscometer manufactured by Tokimec Co., Ltd.
The value of less than p is measured with a standard cone rotor at 1 rpm of an ELD viscometer manufactured by Tokimec Co., Ltd.
The value of less than p was measured by an ELD viscometer ST-type rotor 20 rpm manufactured by Tokimec Co., Ltd. (Measurement temperature 25 ° C)

Example 1 63.0 parts of purified water C.I. I. Direct Black 19 7.0 parts Ethylene glycol 10.0 parts 2% aqueous solution of PEMULEN TR-1 (compound represented by the above general formula (Chemical Formula 2), manufactured by Good-rich, USA) 15.0 parts Xylit 5. 0 parts After mixing the above components and stirring for 1 hour, a 25% aqueous sodium hydroxide solution (pH adjuster) was added to adjust the pH to 7.5, followed by filtration to obtain a black ink having a viscosity of 800 cp.

Example 2 75.75 parts of purified water C.I. I. Acid Red 87 5.0 parts C.I. I. Acid Orange 56, manufactured by Orient Chemical Industry Co., Ltd. 1.0 part Propylene glycol 10.0 parts 1,2-Benzoisothiazolin-3-one 0.2 parts PEMULEN TR-2 (in the above formula (Chemical Formula 2) Compound shown, 2% aqueous solution of Good-rich, USA 5.0 parts Guar gum 0.05 parts PO-500 (monosaccharide alcohol / polysaccharide alcohol mixture, manufactured by Towa Chemical Industry Co., Ltd.) 3.0 parts The components were mixed, heated to 40 to 50 ° C. and stirred for 1 hour, and then the pH was adjusted to 8.5 by adding a 25% aqueous sodium hydroxide solution, followed by filtration to obtain a red ink having a viscosity of 200 cp.

Comparative Example 1 Purified water 66.0 parts I. Direct Black 19 7.0 parts Ethylene glycol 12.0 parts PEMULEN TR-1, 2% aqueous solution 15.0 parts After mixing the above components and stirring for 1 hour, 25% aqueous sodium hydroxide solution (pH adjuster) was added. The mixture was adjusted to pH 7.5 and filtered to obtain a black ink having a viscosity of 800 cp.

Comparative Example 2 48.0 parts of purified water I. Direct Black 19 7.0 parts Ethylene glycol 30.0 parts PEMULEN TR-1, 2% aqueous solution 15.0 parts After mixing the above components and stirring for 1 hour, 25% aqueous sodium hydroxide solution (pH adjuster) was added. The mixture was adjusted to pH 7.5 and filtered to obtain a black ink having a viscosity of 800 cp.

[0028]

<Test 1> Examples 1 and 2 and Comparative Examples 1 and 2
Is filled in a ballpoint pen K105 (ball diameter 0.5 mm, which holds the ink in a transparent hollow container) manufactured by Pentel Co., Ltd., and the pen tip is exposed to the outside air at a temperature of 50 ° C. and a humidity of 30%. After standing for 24 hours, writing was performed, and the length of the faint writing line from the start of writing until the ink came out was measured.

<Test 2> The ink lines of Examples 1 and 2 and Comparative Examples 1 and 2 were filled in a ballpoint pen K105 manufactured by Pentel Co., Ltd., and the writing line width when writing on fine paper (basis weight 70 kg) was measured with a tool microscope. (STM-C type, manufactured by Olympus Optical Co., Ltd.). Table 1 shows the results of Tests 1 and 2.

[0030]

[Table 1]

As described above, when the ink of the present invention is assembled into a ball-point pen, the ink remaining amount can be confirmed.
Although it is a water-based ink for a ball-point pen having a viscosity capable of holding the ink in a transparent or translucent container such as a pipe, it is excellent in drying resistance at a pen tip and can obtain a handwriting which is hard to bleed.

Claims (1)

(57) [Claims] At least a coloring material, water, and a resin for thickening.
In the aqueous ink composition for ballpoint pens comprising
The thickening resin is a compound represented by the following general formula (Formula 1)
And / or salts thereof, further containing a sugar alcohol
And the viscosity of the ink composition is 50 cp or more and 2000 cp or less.
Below is an aqueous ink composition for a ballpoint pen. Embedded image