JP2001019890A - Aqueous ink composition for ballpoint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink composition which gives handwritten lines exhibiting a good erasabilty with an eraser even when left as it is for a long term by using 'High-Stretch Latex' (a resistered trademark) as the resin for an ink containing water, a pigment, and a resin. SOLUTION: Three brands, V-29, V-43, and V-60, of 'High-Stretch Latex' are used, the amounts of them contained in the ink being usually 5-70 wt.%. Other latices can be jointly used as the resin, Though usually used organic pigments and carbon black may be used as the pigment, colored spherical particles such as 'Epocolor' (a registered trademark) and 'Rubcouleur' (a registered trademark) are especially favorable. The pigment is used usually in an amount of 10-20 wt.% of the ink. This latex completely returns to its original state even after repeated expansion and contraction, exhibiting a very small hysteresis loss and hence having high resistances to heat and light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen ink which can be erased with an eraser after writing on paper.

[0002]

2. Description of the Related Art Generally, ballpoint pen ink is not limited to oil-based ink and water-based ink, and cannot be erased with an eraser after writing on paper. In the case of oil-based ballpoint pens, there have been examples of the development of inks that can be erased with an eraser, but they are incomplete (JP-A-57-36173).

[0003] Japanese Unexamined Patent Publication No. Hei 10-195366 discloses natural rubber,
There is disclosed an example of developing an aqueous erasable ink using a latex of rubber such as styrene-butadiene rubber and acrylonitrilo rubber. However, although the erasability immediately after writing is good, the erasability of the handwriting after a long time has elapsed after writing is significantly deteriorated.

[0004]

[Means for Solving the Problems] Among rubber latexes, a special latex with the brand name of "High Stretch Latex" was used, and it was found that the erasability did not change even if the handwriting was left for a long time. . The biggest difference between this latex and other latexes is that even if the latex is repeatedly expanded and contracted, it completely returns to its original state and the hysteresis loss is very small. Therefore, it has strong resistance to heat and light.

[0005] "High stretch latex" is a trade name of BF Goodrich and seems to be a special acrylic latex. It's not clear because it's a trade secret that doesn't reveal details. In Japan, Gunze Sangyo Co., Ltd. sells three brands of V-29, V-43 and V-60 in Japan.

The "high stretch latex" used in the present invention is the above three brands. The amount used in the ink is 5
７０70% by weight, preferably 20-50% by weight. If the used amount is too small, the erasing performance is insufficient, and if the used amount is too large, the ejection of ink from the ballpoint pen deteriorates. When using "high stretch latex" for the purpose of improving ink performance, other latexes can be used in combination.

The pigment which can be used in the present invention may be an ordinary commercially available organic pigment or carbon black. Particularly preferred is a colored spherical particle such as Epocolor of Nippon Shokubai Kagaku or Labolorol of Dainichi Seika Kogyo. It is. The amount of use depends on the coloring power of the particles and cannot be unconditionally determined, but is usually 10 to 20% in the ink.

It is a matter of course that a surfactant, a thickener, a preservative, glycerin and the like can be added to the ink of the present invention, if necessary.

[0009]

EXAMPLES The present invention will be described in more detail with reference to examples.

Example 1 8 parts of water, 14 parts of Epocolor FP113 manufactured by Nippon Shokubai Chemical
Department, Daiichi Kogyo Pharmaceutical Plysurf A210G 0.5
Nippon Unicar Silicone Emulsion LE-45
2 parts, glycerin 5 parts, defoamer 0.1 part, preservative 0.2 part, thickener (xanthan gum) 0.2 part,
50 "High Stretch Latex" (V-60)
And 10 parts of SBR latex 0561 manufactured by JSR were sufficiently mixed to obtain an ink. Writing was performed on paper with a ball-point pen filled with this ink, left for one month at room temperature, and then erased with an eraser.

Example 2 In Example 1, “high stretch latex” was used.
(V-60) 30 parts of "High Stretch Latex" (V-29) instead of 50 parts, SBR latex 05
SBR latex 0561 3 instead of 10 parts 61
An ink was obtained in the same manner as in Example 1 except that 0 part was used. Write on paper with a ballpoint pen filled with this ink,
After leaving it at room temperature for one month, it was erased with an eraser, showing good erasability.

Comparative Example 1 An ink was obtained in the same manner as in Example 1 except that only 50 parts of SBR latex 0561 was used as the latex. After writing on paper with a ballpoint pen filled with this ink, leaving it at room temperature for one month and then erasing it with an eraser, almost no erasure was possible.

[0013]

The ballpoint pen filled with the ink of the present invention shows good erasability by the eraser even if the handwriting is left for a long time.

Claims (1)

[Claims] 1. An aqueous ink composition for a ballpoint pen, wherein the resin is at least water, a pigment, and a resin, wherein the resin is “High Stretch Latex” (trade name of BF Goodrich).