JPS5863766A - Ink composition - Google Patents

Abstract

PURPOSE:A writing ink composition that is prepared by adding a water-soluble macromolecular compound together with dyes and pigments to an aqueous medium, thus being erasable with commercially available erasers, when letters and drawings are written with this ink. CONSTITUTION:The objective ink composition is obtained by adding (A) a water- soluble macromolecular compound such as starch, arabic gum, gelatin, polyvinyl alcohol, polyethylene oxide, sodium polyacrylate or polymethacrylate or sodium alginate, preferably a compound containing metal salts, preferably by 0.1-8wt%, (B) a dye or pigment, preferably O/W type emulsion pigment, preferably by 0.1-15wt% and, when necessary, (C) glycerol, preferably by 3-40wt%, to an aqueoue medium. EFFECT:The resultant ink can write letters and drawings without blotting even on erased places.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel ink composition, and more particularly to a writing ink composition from which written characters and strokes can be erased with a commercially available erasing comb.

When writing ink used in conventional fountain pens and signboards is written on paper, it is almost impossible to erase the written information with an eraser. Eraser fluid is generally employed to erase information written with conventional ink. however,
When using this type of erasing liquid, the erased marks are in a wet state, so it is not possible to write on them immediately, and in order to write on the erased marks again, the erased marks must be completely dry. I needed to do it. Even if characters are written while the eraser remains wet with the eraser, the characters may smudge or be erased again by the action of the eraser.

The inventors of the present invention have conducted extensive research to develop an ink composition that allows written characters and strokes to be easily erased with a conventional eraser, without using the above-mentioned eraser. The inventors have also discovered that an aqueous ink composition formed by adding a pigment or dye together with a water-soluble polymer compound to an aqueous medium is suitable for the purpose, and have completed the present invention.

As the water-soluble polymer compound used in the present invention, for example,
Starch, agar, gum arabic, dextrin, gelatin, carboxymethyl cellulose, sodium alginate, solubilized starch, sodium caseinate and other natural polymer compounds or their various modified products, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, sodium polyacrylate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, sodium polyacrylate, Examples include synthetic polymer compounds such as sodium methacrylate and polyacrylamide. In the present invention, it is particularly preferable to use those having a metal base such as sodium polyacrylate and sodium alginate. When these water-soluble polymer compounds are included in ink and written on paper, they form a unique film on the paper, which also delays the permeation of dissolved pigments into the paper. , to make it easier to remove the pigment from the paper surface when erasing with an eraser. The concentration of the polymer compound varies depending on its type and molecular weight, but in order to form an aqueous ink, a low concentration is sufficient, and usually 1.
It is 0% by weight or less.

The dye or pigment used in the present invention is not particularly limited, and direct dyes, acid dyes, basic dyes, reactive dyes, and various pigments are applicable. In the present invention, oil-in-water (0/W) emulsion pigments are preferably used. In addition, this O
/W-type emulsion pigments use water as a continuous phase and emulsify water-insoluble organic solvents and resins in the presence of an emulsifier.
Furthermore, it is formed by dispersing pigment particles in water. The concentration of the dye or pigment is not particularly limited as long as it provides an appropriate ink concentration, but is generally 0.05 to 2.
It is 0% by weight.

In the present invention, when adding a polymer compound and a dye or pigment to an aqueous medium, it is necessary to take care to prevent the two from reacting to form a precipitate. -1, or add an appropriate amount of acid, base, etc. as a solubilizer or suspending agent. Water is usually used as the aqueous medium, but if necessary, alcohol,
They can also be used in the form of mixtures with water-miscible organic solvents such as ethers, amines, ketones, amides, fatty acids and the like.

In addition to the above-mentioned components, various additives can be added to the ink composition of the present invention. For example, as an anti-drying agent,
Glycerin and polyalkylene dalicol can be added, and other viscosity modifiers can also be added. The amount of such auxiliary additive components used is 1 to 20% by weight, preferably 5 to 15% by weight, and is appropriately selected depending on the type of the additive component.

Preferred ink compositions according to the invention contain no pigment or dye.
．． 05 to 20 heavy dragons, preferably o, i to 15 heavy dragons,
Polymer compound 0.05 to IO weight %, preferably 0.1
It contains 1 to 50% by weight of glycerin, preferably 3 to 40% by weight, if necessary.

The ink composition of the present invention is applied as a writing ink, and is preferably applied as an ink for stroke order of felt-tip pens, ballpoint pens, fountain pens, and the like. Characters and lines written using the ink composition of the present invention can be erased with a commercially available eraser, and the erased traces can be written on again without causing any bleeding of letters or lines. can do.

The ink composition of the present invention is preferably used as a stroke order ink as described above, but it can be used for type printing by adding an appropriate fixing agent to make it easy to apply to the surface of paper or cloth. It can also be used as ribbons and various copying inks.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Glycerin l and 0.5 g of sodium polyacrylate (degree of polymerization 22,000 to 66,000) were dissolved in 100 g of water, and 9 g of an emulsion type pigment (HeliZyrin Black 7TT) was dissolved therein to form a uniform black ink. It was created. Next, the filling of the felt-tip pen was impregnated with this i7li, so that it leached out from the pen core. When I wrote letters on paper with this pen and erased them with a commercially available eraser, the letters were erased. Furthermore, when another character was immediately written on this erased trace, the character was written in a normal state without any bleeding or the like.

Example 2 In the same manner as in Example 1, an ink composition having the following component composition was prepared.

Table 1 (Ink composition) (c, r indicate color index) Using the ink composition having the component composition shown in Light 1 above, an erasing test of written characters was conducted in the same manner as in Example 1. As a result, it was confirmed that all of the images could be erased with an eraser. In addition, in the case where a water-soluble polymer compound is not added to the above composition, the ink permeates into the paper surface quickly, and even if characters are written and attempted to be erased with an eraser, they cannot be completely erased. Ta.

Agent Patent Attorney Toshiaki Ikeura Procedural Amendment (Method) % Formula % 1, Case Indication 1982 Patent Application No. 712-f76
No. 2, Title of the invention Ink composition 3, Relationship with the case of the person making the amendment Patent applicant address False if&-&*1175-6, Urama City, Saitama Prefecture Name Adgar Industries Co., Ltd. Representative Senior Kaoru Kakan Washi 4. Indication of agent 141 Telephone number (443) 4017 5. Date of amendment order Voluntary action 6. Subject of amendment Full text of specification 4

Claims (1)

[Claims] (1) An ink composition characterized in that a dye or pigment is added together with a water-soluble polymer compound in an aqueous medium.