JP2000080318A - Water ink composition for ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficient antirust effect by incorporating solvents containing water and glycerin, a coloring agent and a polymer for imparting viscosity reducing property. SOLUTION: This ink composition contains a solvent including 26-49 wt.% of water and 30-45 wt.% of glycerin, 3-20 wt.% of a coloring agent and a polymer for imparting viscosity property reducing. As the coloring agent, a pigment or a dye which is conventionally used as water ink for a ballpoint pen can be used. The polymer is the one to give thixotropy characteristics such as xanthan gum, sodium alginate, carrageenan gum, carrageenin, locust bean gum, hydroxyethyl cellulose or guar gum. The solvent containing water and glycerin can include water-soluble organic solvents except glycerin, for example, ethylene glycol, propylene glycol, ethanol 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 water-based ink composition for a ball-point pen, and more particularly to a water-based ink composition for a ball-point pen having a reduced viscosity.

[0002]

2. Description of the Related Art Conventionally, aqueous ink compositions of this type are mainly composed of a pigment or dye coloring agent, water and / or water.
Or a water-soluble organic solvent, a viscosity reducing polymer, a dispersant, a lubricant,
It generally contains a rust inhibitor, a preservative, a pH adjuster, and the like.

[0003]

However, since the ink is a water-based ink, when the ink is incorporated into a ballpoint pen, there is a problem that the metal tip portion at the tip rusts in a long time. By containing a rust inhibitor,
Although it can certainly have a rust-preventing effect, it is not always perfect, especially when exposed to long-term storage or high temperatures. Therefore, in particular, there is a problem that the portion of the metal chip that is in contact with the ink of the ball is deteriorated and loses luster, and writing is not smooth. The present inventor has made an effort to solve the above problems, and as a result, has come to invent a water-based ink composition which can have a sufficient rust-preventing effect.

[0004]

That is, according to the present invention, 26 to 49% by weight of water and 30 to 4%
The gist of the present invention is to contain a solvent containing 5% by weight of glycerin, 3 to 20% by weight of a colorant, and a polymer for imparting viscosity reduction. By increasing the glycerin content and reducing the water content as much as possible, the evaporation of the solvent is suppressed as much as possible, and the surface of the ball that is exposed in contact with air is always covered with ink. Of the ball can be suppressed, and the gloss of the ball surface can be maintained.

As the colorant, pigments and dyes conventionally used for aqueous ballpoint pen inks can be used. Examples of the pigment include carbon black, titanium oxide, and titanium oxide.
Iron black, navy blue, ultramarine, chromium oxide, carmine 6B, C.I.
I. Pigment Red 104, 112 and C.I. I. Pigment Blue 15, 27 and C.I. I. Pigment Green 7, C.I. I. Pigment Yellow 3, 34 and the like. Among the direct dyes, direct black (C.I.
I. 17), (19), (32), Daiwa Black 320HSW, Daiwa Black MR, Direct Deep Black EX (CI. 35435), Direct Blue 2B (CI. 22610), Direct Blue (CI) 71), (93), Direct Red (CI.4), (23), (37), and acid dyes of Acid Black (CI.24), (31), Acid Red ( C.I.8), (14), Acid Blue (C.I.1), (7), Acid Violet (C.I.15), other food dyes, basic dye Auramine 0 (C.I. .41000), Victoria Blue (CI.44045), Rhodamine 6GCP (C.I.
I. 45160), Daiwa Red No. 104 (CI.9)
2) and the like. In addition, as the polymer that imparts viscosity reduction, a polymer that provides thixotropic properties such as xanthan gum, sodium alginate, carrageenan gum, carrageenan, locust bean gum, hydroxyethyl cellulose, and guar gum can be used.

The solvent containing 26 to 49% by weight of water and 30 to 45% by weight of glycerin can contain a water-soluble organic solvent other than glycerin. As a water-soluble organic solvent other than glycerin, alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butylene glycol, and ethanol, and pyrrolidone, N-methyl-2-pyrrolidone, and dimethylformamide are used alone or in combination. Can be used. Further, in addition to the above, a lubricant, a rust inhibitor, a preservative, a pH adjuster, and a surfactant can be added.

As the lubricant, phosphate ethers such as polyoxyethylene alkyl ether phosphoric acid, and alkali salts of fatty acids such as potassium oleate can be used. As rust inhibitors, benzotriazole,
Benzimidazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite and the like can be used. As preservatives, biocide (Nippon Synthetic Chemical), Proxel (ICI Japan) and the like can be used. P
As the H adjustor, triethanolamine, sodium hydroxide, aqueous ammonia, urea, monoethanolamine, diethanolamine, sodium tripolyphosphate, sodium carbonate and the like can be used. As the surfactant, nonionic, anionic surfactants and the like can be used.

[0008]

Next, the contents of the present invention will be described by way of examples.

[0009]

(Example 1) Black pigment 6% by weight Glycerin 40% by weight Water 46% by weight Xanthan gum 0.3% by weight Benzotriazole 0.3% by weight Bioside 0.4% by weight Triethanolamine 6% by weight Polyoxyethylene Alkyl ether phosphoric acid 1% by weight

As the pigment, a pigment dispersion (12% by weight of pigment, 20% by weight of glycerin, 68% by weight of water) is used, and the above mixture is stirred well with a propeller mixer (40 ° C.) to obtain a uniform aqueous ink. Obtained. This ink composition was filled into a ballpoint pen refill, and the tip was capped.
After storage at 0 ° C. for 3 months, the surface of the ball in contact with the air was observed and found no abnormality in gloss.

[0011]

(Example 2) Black pigment 6% by weight Glycerin 30% by weight Ethylene glycol 20% by weight Water 35% by weight Sodium alginate 0.5% by weight Benzotriazole 0.3% by weight Biocide 0.4% by weight Triethanolamine 6% by weight Potassium oleate 1.8% by weight

Ink was prepared in the same manner as in Example 1, filled into a ballpoint pen refill, capped at the tip and stored at 50 ° C. for 3 months, and the surface of the ball in contact with air was observed. As a result, no abnormality was found as in Example 1.

[0013]

Comparative Example 1 Black pigment 6% by weight Glycerin 20% by weight Ethylene glycol 10% by weight Water 55% by weight Sodium alginate 0.5% by weight Benzotriazole 0.3% by weight Biocide 0.4% by weight triethanolamine 6% by weight Potassium oleate 1.8% by weight

Ink was prepared in the same manner as in Example 1, filled into a ballpoint pen refill, capped at the tip, stored at 50 ° C. for 3 months, and observed the surface of the ball in contact with air. As a result, the hemisphere in contact with the air lost its luster.

[0015]

As described above, by increasing the glycerin content and minimizing the water content,
Evaporation of the solvent is suppressed as much as possible, so that the exposed portion of the ballpoint pen that comes into contact with the air is always covered with the ink, thereby preventing the generation of rust.

Claims (1)

[Claims] 1. The composition according to claim 1, wherein the total amount is 100 to 100% by weight.
A water-based ink composition for a ball-point pen, comprising: a solvent containing 30% by weight of water and 30% to 45% by weight of glycerin; 3% to 20% by weight of a colorant; and a polymer for imparting viscosity reduction. object.