JPH04239069A - Ink composition - Google Patents

Abstract

PURPOSE:To provide an ink which has a sufficient hiding power, enables writing or drawing of distinct characters or pictures even on a dark object, and gives drawn lines erasable with water without fail. CONSTITUTION:When lines are drawn on an object using an ink compsn. comprising a water-sol. white powder finely dispersed in a hydrophilic org. solvent having a low strength of dissolving the powder, the solvent evaporates rapidly and the powder remains on the object to form the lines. When the lines are wiped with a cloth soaked with water, the white powder dissolves into water and the lines are erased.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a novel ink composition, and more specifically, it is used to clearly draw lines and characters even on objects such as black or dark-colored cloth, leather, and paper. The present invention relates to an ink composition that can be erased reliably with water.

0002

[Prior Art] Conventionally, black or dark-colored fabrics, leather,
When drawing lines and characters on objects such as paper, white pigment-based inks are used because dye-based inks have poor hiding power as a base and lack sharpness. However, lines and characters drawn with such ink cannot be completely erased. Therefore, in order to solve the above-mentioned problems,
No. 12 discloses an ink using zinc ammine complex salt,
Japanese Patent Publication No. 1-26631 proposes an ink using a higher alkyl sulfate.

0003

[Problems to be Solved by the Invention] However, in the ink disclosed in the above-mentioned Japanese Patent Publication No. 62-25712, in which a zinc ammine complex salt is dissolved in an aqueous solvent, ammonia evaporates during the process in which the transparent ink turns white on cloth, etc. Since it involves acid and also uses ammonia water during erasing, it is not very practical in terms of odor.

On the other hand, in the ink disclosed in Japanese Patent Publication No. 1-26631 in which a higher alkyl sulfate is dispersed in glycerin, sufficient whiteness cannot be obtained, probably because the refractive index of the higher alkyl sulfate and glycerin are close to each other. For this reason, even if the image is actually drawn on a dark-colored cloth, it cannot be visually confirmed, so it cannot be said that the purpose has been achieved.

The present invention was made to solve the above-mentioned problems, and the hiding power of the base is sufficient, so that clear characters and drawing lines can be drawn even on dark-colored objects, and The object of the present invention is to provide ink in which the image area is water and can be reliably erased.

[0006]

[Means for Solving the Problems] In order to achieve this object, the ink composition of the present invention has a structure in which a water-soluble white powder is finely dispersed in a hydrophilic organic solvent that has a small dissolving power for the powder. ing.

[0007] Furthermore, for dark-colored objects including white parts, it is possible to use a combination of a leuco dye and a water-soluble color developer to color the ink, thereby producing a colored ink that has a base-hiding ability.

[0008]

[Operation] When characters, lines, etc. are drawn on an object using the ink composition of the present invention having the above-mentioned structure, the solvent of the ink quickly permeates or evaporates into the object. Most of it disappears from the surface of the object to be drawn. On the other hand, most of the finely dispersed white powder accumulates on the surface of the object to be drawn, forming characters, drawing lines, etc. Next, to erase the image area, wipe it with a cloth dampened with water or wet it with water, and the white powder that makes up the image area will dissolve in the water and penetrate into the object to be drawn. disappears due to Moreover, even after the water dries, no residue remains on the area.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to the drawings.

The ink composition of this example is a white ink made by finely dispersing white powder in a hydrophilic organic solvent having a low dissolving power. The white powder used here must be appropriately selected from the viewpoint of erasability and fastness required of the ink, ranging from those with high to low solubility in water. In other words, if the erasability is to be maximized, sugars such as sucrose and glucose, or alkali metal salts of organic acids and inorganic acids are suitable.On the other hand, if the ability to be erased even with a steam iron is required, organic acids such as amino acids are suitable. , inorganic weak acid/base salts can be used. If further whiteness hiding power is desired, it can be achieved without sacrificing erasability by adding a white pigment such as titanium oxide or calcium carbonate in an amount of 5% by weight or less.

[0011] Next, as the solvent used here, various cellosolves, carbitol, carbitol acetate, ketone alcohols, monohydric alcohols, polyhydric alcohols, etc. can be used alone or in combination, taking into consideration the drawing method, drying speed of drawing, etc. Adjust.

By the way, if it is necessary to firmly fix the white powder onto the object to be drawn, it is sufficient to add a resin to the ink that is water-soluble and also dissolves to some extent in the hydrophilic solvent, such as hydroxypropyl cellulose, Methylcellulose, ethylcellulose, etc. meet this requirement.

The ink having the above structure is white and is clear on dark-colored objects, but may be difficult to see on dark-colored objects containing white parts. Such ink is colored by adding a leuco dye and a water-soluble color developer to the white ink to develop color. Any hue can be obtained by selecting a leuco dye, and a colored ink with hiding power for the base can be realized.

[0014] As the leuco dye, a normally colorless dye conventionally used in heat-sensitive and pressure-sensitive recording can be used, while as a water-soluble color developer, a phenolic substance with a sulfonic acid group introduced therein, such as P-toluenesulfonic acid, naphthalene sulfonic acid, P-sulfosalicylic acid, sulfonated bisphenol,
Also effective are sulfonated phenol resins, hydroxycarboxylic acids such as lactic acid and tartaric acid, and water-soluble thiocyanate metal salts, especially zinc salts.

[0015] Of course, characters and lines drawn with colored ink as described above can also be erased by applying water. The white powder component present in the image area disappears as described above, and the colored dye is decolored by the color developing component diffusing into the object to be drawn by water and separating from the leuco dye.

An example based on the above content will be shown below.

(Example 1) Sodium glutamate (Kyowa Hakko)
180 parts by weight
Hydroxypropylcellulose (Nippon Soda HPC-S
L) 15 parts by weight Sorbitan sesquioleate (Kao Arlacel 83)
5 parts by weight ethyl cellosolve

200 parts by weight Butyl cellosolve

50 parts by weight First, a predetermined amount of hydroxypropylcellulose is dissolved in the above-mentioned mixture of ethyl cellosolve and butyl cellosolve, and after adding a predetermined amount of sorbitan sesquioleate to the solution, sodium glutamate is added and sufficiently pre-stirred. Make a homogeneous suspension. Next, the suspension is wet-pulverized using a sand mill or the like to obtain a fine dispersion having a particle size distribution of about 0.4 to 4.0 μm.

When letters and figures were drawn on dark-colored cloth using the obtained ink 5 using two methods: the ballpoint pen 6 shown in FIG. 1 and the air-jet plotter shown in FIG. 2, the result was a clear white color. I was able to draw with sufficient adhesion. Moreover, the next time the image area was erased, just one spray of water with a sprayer completely erased it, and even after the water evaporated, no trace remained.

(Example 2) L-glutamic acid

200 parts by weight Leuco dye Blue 3NB (
Yamamoto Kasei)
2 parts by weight tartaric acid

15 parts by weight lactic acid

4
0 parts by weight Hydroxypropyl cellulose (Nippon Soda HPC-L) 10 parts by weight Ethyl cellosolve
200 parts by weight diacetone alcohol

50 parts by weight of L-glutamic acid was added to an ethyl cellosolve solution in which hydroxypropylcellulose was dissolved, and the mixture was wet-pulverized in a sand mill to obtain a white ink similar to that in Example 1. Separately, a predetermined amount of tartaric acid and lactic acid are added and dissolved in diacetone alcohol, and then a blue ink composition is prepared by adding dye Blue3NB to dissolve and develop color, and mixed with the white ink. Here you will get a blue ink with hiding power. When this ink was used to draw on a checkered fabric with alternating white and dark colored areas in the same manner as in 1 above, clear lines were obtained in the areas described above. Draw on the drawing object 1
After a while, I tried steam ironing it, but the lines didn't disappear at all and the clarity remained the same. Next, when a sufficient amount of water was applied to the drawn area by spraying, the image gradually disappeared, and when the water was completely evaporated and dried, the image completely disappeared.

(Example 3) L-glutamic acid

230 parts by weight Titanium oxide (anatase type)

13 parts by weight polyethylene glycol

280 parts by weight ethylene glycol

300 parts by weight When the inks of Examples 1 and 2 continue to draw for a long time with the air jet plotter, powder gradually accumulates on the nozzle tip 8 in FIG. 2(a) due to the drying properties of ethyl cellosolve. Indicates a tendency for holes to clog. In order to prevent this, Example 3 uses a solvent with low volatility. When drawing was performed using the air jet method described above on a dark-colored cloth using the ink prepared in the same manner as in Example 1 with the composition according to this example, no phenomenon such as hole clogging occurred at all even when drawing was performed intermittently for a long time. It didn't happen. Immediately after drawing, the image area was not as clear as in Examples 1 and 2, but after about 10 minutes, the high-boiling point agent had penetrated into the object, and as a result, it became as clear as in Examples 1 and 2. The situation became clear. Furthermore, the erasability with water was sufficient, with no residue left, even though water-insoluble titanium oxide was added, since the amount was small.

[0021]

[Effect of the invention] As is clear from the detailed description above,
By using the ink composition of the present invention, it is possible to draw clear and adhesive characters and drawing lines on objects such as fabrics, leather, paper, etc. of all hues and patterns including black or dark colors, and You can definitely erase it with . Furthermore, by selecting the degree of water solubility of the white powder used, it is possible to create an ink that does not disappear with a steam iron but disappears with water.

[0022] Therefore, when drawing cutting lines and sketches in dressmaking, embroidery, etc., this ink can be used on any target fabric without restriction, and can also be steam ironed during sewing, and can be easily cleaned after use. , can be erased with water. Moreover, since the fluidity of the ink can be adjusted appropriately, it can be applied not only to the chalk pen type but also to various types of printing equipment such as the jetting type, and its utility value is great.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a ballpoint pen in which the ink of this example is used as a chalk pen.

FIG. 2 is a diagram showing an air jet type plotter using the ink of this example.

[Explanation of symbols]

6 Ballpoint pen 7 Plotter

Claims (3)

[Claims] 1. An ink composition comprising a water-soluble white powder finely dispersed in a hydrophilic organic solvent having a small dissolving power. 2. The ink composition according to claim 1, which is colored by adding a normally colorless leuco dye and a water-soluble color developer. 3. The ink composition according to claim 1, wherein a white pigment such as calcium carbonate or titanium oxide is liquefied in an amount of 5% by weight or less.