JPH11310744A - Aqueous ink for ball-point - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aq. ink which has a stable quality and does not exhibit the degradation in usability in writing after a long storage by incorporating at least a dye, L-ascorbic acid, dipolyoxyethylene alkyl ether phosphoric acid, and water into the same. SOLUTION: This ink at least comprises a dye pref. comprising a direct or acidic dye which is stably soluble at a neutral to alkaline pH; L-ascorbic acid or its alkali metal salt, pref. in an amt. of 0.2-5.0 wt.% of the ink; dipolyoxyethylene alkyl ether phosphoric acid or its alkali metal salt, pref. having a number of moles of oxyethylene unit added of 2-8 and pref. in an amt. of 0.5-5.0 wt.%; and water, pref. in an amt. of 30-95 wt.%. L-ascorbic acid acts as an antioxidant, and dipolyoxyethylene alkyl ether phosphoric acid contributes to rust prevention and aging stability of solubility of a dye.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water-based ink for a ball-point pen using a dye. More specifically, the present invention relates to a water-based ink for a ball-point pen, in which the rotation of a ball is smooth even after a long period of time, and which exhibits excellent writing quality.

[0002]

2. Description of the Related Art Conventionally, aqueous inks for ballpoint pens contain at least a dye, water and a water-soluble organic solvent. The dye forms a handwriting as a coloring agent. Water dissolves dyes and other substances as the main solvent. The water-soluble organic solvent not only functions as a solubilizing agent for stably dissolving the dye over time, but also plays a role in adjusting the nib drying property. In addition, various water-based surfactants, such as silicone oil and fluorine-based surfactants, are added to the water-based ink for ballpoint pens to prevent wear of the ball seat and to improve the writing distance, and to smooth the writing taste. It is known that various lubricants are added to the oil. Further, in order to prevent corrosion of metal members such as balls and the occurrence of mold on ink, it is common practice to add a rust inhibitor or a preservative.

[0003]

However, in recent years, there has been a demand for highly safe inks that do not use highly toxic or dangerous chemical substances in consideration of the effects on the human body and the environment. Especially with oil-based inks, the tendency is stronger,
Even in water-based inks, thiodiglycol, which is often used in water-based inks as a dissolution aid for dyes, is designated as a precursor to chemical weapons in the Act on the Prohibition of Chemical Weapons and the Regulation of Specific Substances, etc. Employers must notify the Minister of Commerce and Industry of their planned use quantity and past performance, and would like to avoid using them as much as possible. However, if the composition of the ink is made closer to water, it becomes unstable with time, affects writing characteristics, and affects various writing characteristics. In addition, when the amount of the water-soluble organic solvent is reduced or the type thereof is limited, the sedimentation of the dye with the passage of time and a decrease in writing taste due to a decrease in lubricity of the ball surface occur. An object of the present invention is to provide a water-based ink for a ball-point pen using a dye, in which the writing quality after long-term storage does not decrease without using thiodiglycol, and which maintains stable quality. As an issue.

[0004]

SUMMARY OF THE INVENTION The gist of the present invention is an aqueous ink for a ball-point pen, which comprises at least a dye, L-ascorbic acid, dipolyoxyethylene alkyl ether phosphoric acid, and water.

The details will be described below. As the dye, any of direct dye, acid dye, basic dye and the like can be used, but depending on the type of ball or chip material,
If the pH is low, corrosion may occur. Therefore, it is preferable to use a direct dye or an acid dye which has a neutral to alkaline pH and stably dissolves. An example is given below.

As direct dyes, C.I. I. Direct Black 17, 19, 22, 22, 32, 5
1, and 71, C.I. I. Direct Yellow 4, 26, 44, 50, C.I. I. Direct Red 1, Same 4, Same 23, Same 31, Same 37, Same 39, Same 75, Same 80, Same 8
1, 83, 225, 226, 227, C.I. I.
Direct Blue 1, 15, 15, 71, 86, 10
6, 199 and the like.

[0007] Acid dyes include C.I. I. Acid Black 1, 2, 24, 26, 31, 31, 52, 1
07, 109, 110, 119, 154, C.I.
I. Acid Yellow 7: 1, 17, 17, 19, 23,
25, 29, 38, 42, 49, 72, 61, 78, 110, 141, 135, 12
7, 142, C.I. I. Acid Red 8, 9 and 1
4, 18, 18, 26, 35, 37, 5
1, 52, 57, 82, 87, 92, 9
4, 111, 129, 131, 138, 18
6, 249, 254, 265, 276, C.I.
I. Acid Violet 15, 17 and C.I. I. Acid Blue 1, 7, 9, 15, 22, 23,
25, 40, 41, 43, 62, 78, 83, 90, 93, 103, 112, 11
3, 158, C.I. I. Acid Green 3, 9, 16, 25, 27, and the like.

The basic dyes include C.I. I. Basic Blue 7, C.I. I. Basic Red 1 and the like.

In the present invention, L-ascorbic acid and dipolyoxyethylene alkyl ether phosphoric acid are used to improve the stability over time in a water-based ink for a ballpoint pen using a dye and to maintain good writing taste. Note that L
-Ascorbic acid and dipolyoxyethylene alkyl ether phosphoric acid may be used as free acids or alkali metal salts such as sodium salts. The amount of L-ascorbic acid used is preferably from 0.2 to 5.0% by weight, more preferably from 0.5 to 3.0% by weight, based on the total amount of the ballpoint pen aqueous ink.

Specific examples of dipolyoxyethylene alkyl ether phosphoric acid include DDP-2 (dipolyoxyethylene (2) alkyl ether phosphoric acid), DDP-4 (the number of moles of POE added is 4), and DDP-6 ( The same number of moles as POE added 6), DDP-8 (number of moles added as POE 8) (above,
Nikko Chemicals Co., Ltd.). The number of moles of polyoxyethylene added to dipolyoxyethylene alkyl ether phosphoric acid is preferably 2 to 8. The amount of dipolyoxyethylene alkyl ether phosphoric acid used is preferably 0.5 to 5.0% by weight based on the total amount of the water-based ink for ballpoint pens.

Water is used as the main solvent. It is preferable to add 30 to 95% by weight of the water-based ink for a ballpoint pen.

In addition to the above components, ethylene glycol, diethylene glycol,
Glycol-based solvents such as propylene glycol, and conventionally used high-boiling water-soluble organic solvents such as glycerin can be used.However, in consideration of safety, use of thiodiglycol is avoided, Is preferably reduced. Further, conventionally known additives such as a low-boiling water-soluble organic solvent such as alcohol, a polymer substance, a surfactant, a rust preventive, and a lubricant may be appropriately selected and used according to the application.

[0013]

L-Ascorbic acid is known as a highly active antioxidant, and it is easy to imagine that it acts on the antioxidant of the dye in the ink. Also, dipolyoxyethylene alkyl ether phosphoric acid is known to act as a rust inhibitor, and is a known additive for ballpoint pen inks. However, in the case of using the ink which does not use thiodiglycol, which is the object of the present invention, even if each is used alone, it is not possible to obtain a stable ink like the ink using thiodiglycol.
The intended effect can be obtained only by using both substances of the present invention in combination, but the action is presumed as follows. Dipolyoxyethylene alkyl ether phosphoric acid contributes not only to the rust prevention effect but also to the dissolution stability of the dye over time. Although L-ascorbic acid has an antioxidant effect on the dye, it is difficult to maintain its effect for a long period of time because of its immediate effect. Therefore, dipolyoxyethylene alkyl ether phosphoric acid prevents ascorbic acid from being immediately converted to oxidized ascorbic acid, and maintains the original antioxidant effect of ascorbic acid. Even after storage for a long period of time, the dye has excellent dissolution stability, can prevent oxidation on the metal surface, and does not cause deterioration in writing taste.

[0014]

EXAMPLES Example 1 C.I. I. Acid Blue 9 2.0 parts by weight C.I. I. Acid Red 52 1.0 parts by weight L-ascorbic acid 2.0 parts by weight DDP-6 (dipolyoxyethylene (6) alkyl ether phosphoric acid, manufactured by Nikko Chemicals Co., Ltd.) 3.0 parts by weight Water 71.5 Parts by weight Ethylene glycol 10.0 parts by weight Propylene glycol 10.0 parts by weight Proxel GXL (preservative, manufactured by ICI Japan KK) 0.5 parts by weight Each of the above components is stirred and mixed using a stirrer to obtain a blue ink. I got

Example 2 C. I. Acid Blue 15 3.0 parts by weight C.I. I. Acid Red 87 1.0 part by weight L-ascorbic acid 0.5 part by weight DDP-4 (dipolyoxyethylene (4) alkyl ether phosphate, manufactured by Nikko Chemicals Co., Ltd.) 2.0 parts by weight Polyoxyethylene nonyl Phenyl ether 0.1 parts by weight Urea 10.0 parts by weight Water 73.4 parts by weight Ethylene glycol 10.0 parts by weight The above components were stirred and mixed using a stirrer to obtain a blue ink.

Example 3 C. I. Acid Green 3 7.0 parts by weight L-ascorbic acid 1.0 part by weight DDP-2 (dipolyoxyethylene (2) alkyl ether phosphoric acid, manufactured by Nikko Chemicals Co., Ltd.) 4.0 parts by weight Polyoxyethylene ( 2) Cetyl ether 0.3 parts by weight Water 73.7 parts by weight Ethylene glycol 7.0 parts by weight Glycerin 7.0 parts by weight The above components were stirred and mixed using a stirrer to obtain a green ink.

Embodiment 4 C.I. I. Acid Blue 9 7.0 parts by weight L-ascorbic acid 1.5 parts by weight DDP-8 (dipolyoxyethylene (8) alkyl ether phosphoric acid, manufactured by Nikko Chemicals Co., Ltd.) 1.0 part by weight Water 75.5 Parts by weight Propylene glycol 15.0 parts by weight The above components were stirred and mixed using a stirrer to obtain a blue ink.

Example 5 C.I. I. Direct Black 19 9.0 parts by weight C.I. I. Acid Red 8 0.5 parts by weight C.I. I. Acid Bio Red 15 0.5 parts by weight L-sodium ascorbate 1.5 parts by weight DDP-4 (described above) 3.0 parts by weight Water 70.5 parts by weight Glycerin 5.0 parts by weight Propylene glycol 10.0 parts by weight Part The above components were stirred and mixed using a stirrer to obtain a black ink.

Comparative Example 1 A blue ink was obtained in the same manner as in Example 1 except that L-ascorbic acid was used and water was added in the same amount.

Comparative Example 2 A green ink was obtained in the same manner as in Example 3 except that water was added in the same amount as in Example 3 except that DDP-2 was used.

Comparative Example 3 A blue ink was obtained in the same manner as in Example 4 except that L-ascorbic acid and DDP-8 were used and water was added in such amounts.

2.5 g of the water-based ink for a ballpoint pen obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was charged into a commercially available ballpoint pen (Ball Pentel R50, manufactured by Pentel Co., Ltd.), and a ballpoint pen for testing was prepared. Created.

Using the above test ballpoint pen, a test was carried out on the deterioration of the writing taste of those stored for a long period of time. In the writing taste test, a ballpoint pen for a test was prepared and stored at room temperature for one day, and a ballpoint pen was stored in a constant temperature bath at 40 ° C. for three months, taken out and left at room temperature for one day. Table 1 shows the results.

[0024]

[Table 1]

A writing test using a ballpoint pen filled with the above-mentioned ink, a tester capable of converting the writing resistance value into a numerical value, PEN WRITING TE
Using STER (MODEL SP-2, manufactured by Seiki Industry Co., Ltd.), writing speed 4 ± 0.2 m / min, writing load 9
Writing was performed under the conditions of 81 mN (100 gf) and a writing angle of 70 °, and the writing resistance value until the pen rotated one revolution was measured (relative comparison value), and calculated as an average value of the values up to one rotation.

[0026]

As described above in detail, the aqueous ink for a ballpoint pen of the present invention can smoothly rotate the ball and maintain excellent writing quality even after long-term storage.

Claims (2)

[Claims] 1. A water-based ink for ballpoint pens, comprising at least a dye, L-ascorbic acid, dipolyoxyethylene alkyl ether phosphoric acid and water. 2. The aqueous ink for a ballpoint pen according to claim 1, wherein the polyoxyethylene addition mole number of the dipolyoxyethylene alkyl ether phosphoric acid is 2 to 8.