JPH0562078B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a copying material in which copied characters and designs are erased by water.

[Prior art]

2. Description of the Related Art Pressure-sensitive copying materials, such as those found in carbon paper, have been known in which dyes or pigments are coated on a support such as paper or plastic film. Such copying materials are made by overlaying a copying material such as paper on the dye layer or pigment layer, and applying pressure-sensitive copying using a ballpoint pen, iron pen, lourette, etc. to create desired characters or designs on the copying material. can be copied. However, the copies obtained in this manner are usually non-erasable, and there is a problem in that it is extremely difficult to erase the copied characters or designs after they are no longer needed. For example, in sewing, embroidery, lettering, etc., characters and designs are drafted using copy materials, but these drafts are eventually erased.
Conventionally, this erasing is done with an eraser, etc.
It's very troublesome.

In order to eliminate these drawbacks, a transfer paper has been proposed in which an ink containing cobalt thiocyanate mixed with a modified wax obtained by reacting wax with an amine is coated on a support (Japanese Patent Application Laid-Open No. 1986-1999).
Publication No. 166091). This transfer paper has the advantage that the transferred ink can be erased with water, but because it requires the use of a specific wax, it takes time and effort to manufacture, and once the ink has been erased, it looks like it has been erased. Some of the ink that has been removed is mixed in and protected by the wax, so it may become colored again, and there are also disadvantages such as wax-like solids remaining in the erased traces.

〔the purpose〕

The present invention has been made in view of the above-mentioned state of the prior art, and its purpose is to easily and efficiently remove copied characters and designs by adding water, without leaving any solid matter behind the erased traces. To provide a copying material that can be erased visually and is easy to create.

[Structure] That is, according to the present invention, a viscosity containing cobalt thiocyanate and a polyhydric alcohol as a color deepening agent and/or a drying preventive agent, and the content of the polyhydric alcohol is 15 to 60% by weight. A copying material is provided in which a liquid-absorbing support is impregnated with an aqueous solution and whose copied characters and designs can be erased with water.

Further, according to the present invention, the present invention includes a coloring agent consisting of nickel thiocyanate and cobalt chloride, and a polyhydric alcohol as a color deepening agent and/or drying prevention agent, and the content of the polyhydric alcohol is 15 to 60%. weight%
A copying material is provided in which a liquid-absorbing support is impregnated with a viscous aqueous solution of the present invention and whose copied characters and designs can be erased with water.

The colorant for copying used in the present invention is an aqueous solution containing cobalt thiocyanate as a main component. In this case, the solvent for the cobalt thiocyanate solution is water or a mixed solvent of water and an organic solvent. Examples of organic solvents include methanol, ethanol, ether, acetone, chloroform, methyl acetate, and the like. A blue solution can be obtained by dissolving an appropriate amount of cobalt thiocyanate in these solvents. The additive to the cobalt thiocyanate solvent varies depending on the solvent used, but generally it is 0.1 parts by weight per 100 parts by weight of the solvent.
-200 parts by weight, preferably 0.5-140 parts by weight.
In the cobalt thiocyanate solution, it is preferable to add alkylene glycol or polyalkylene glycol as a color deepening agent in order to increase the coloring density. As the polyalkylene glycol, polyethylene glycol, polypropylene glycol, copolymers thereof, etc. are used.
Its molecular weight is not particularly restricted, but is generally 100
-6000, preferably about 200-3000. When such a color deepening agent is used, a deep blue solution can be obtained even when the cobalt thiocyanate concentration is as low as 5 to 20% by weight.

Further, as the colorant for copying of the present invention, a solution containing nickel thiocyanate and cobalt chloride can be used. In this case, as the solvent and the color deepening agent, those mentioned above are used. Regarding the amount of each component added, per 100 parts by weight of the solvent, 0.1 to 120 parts by weight of nickel thiocyanate, preferably 0.5 to 50 parts by weight, 0.1 to 100 parts by weight of cobalt chloride, preferably 0.5 to 90 parts by weight, Coloring agent 2~
The proportion is 30 parts by weight, preferably 5 to 20 parts by weight.

The viscous aqueous solution of the present invention contains an anti-drying agent of 15 to
Contain 60% by weight. In addition, as this anti-drying agent, the alkylene glycol or polyalkylene glycol shown as the color deepening agent can also be used. If the amount of the anti-drying agent added is too small, the evaporation rate of the solution impregnated into the support will increase, making it impossible to obtain a practical product. Moreover, since this anti-drying agent is made of polyhydric alcohol and has viscosity, it also prevents the solution from dripping when the solution is impregnated into a support.

Specific examples of the drying inhibitor include polyhydric alcohols such as glycerin, alkylene glycol, and polyalkylene glycol. Moreover, a water-soluble polymer such as polyvinyl alcohol, starch, sodium alginate, or carboxymethyl cellulose can be added to each of the solutions as a binder.

In the copying material of the present invention, the above solution is impregnated into a liquid-absorbing material as a support, such as paper (particularly filter paper or water-absorbing paper), cloth, liquid-absorbing rubber, liquid-absorbing plastic sheet or film, etc. It can be manufactured by supporting. The impregnating ratio of the solution to the support varies depending on the type of support. Generally, the resulting copy material is surface dry and internally moist, and excess solution can be removed by passing it between pressure rollers.

〔effect〕

In order to make a desired copy using the copying material of the present invention, the copying material is placed on a copying object such as paper or cloth, and a ballpoint pen, pencil, etc.
Pressure-sensitive copying of letters, designs, etc. using a writing instrument such as an iron pen or a Lurette. When pressure-sensitive copying is performed in this way, the colored solution impregnated inside the copying material is transferred to the object to be copied underneath, and the corresponding characters or designs are transferred onto the object to be copied. When the surface of the transferred characters and designs is brought into contact with water-soaked paper, cloth, sponge, etc., the characters and designs are erased. This is based on the principle that when cobalt thiocyanate is diluted with water to a dilute concentration, a dissociation reaction occurs and the coloration substantially disappears.

According to this decoloring principle, when water comes into contact with the transferred characters or designs, the cobalt thiocyanate is diluted and the colored characters or designs are erased, but then, for example, due to evaporation of water, etc. When the cobalt thiocyanate concentration increases to its original level, the letters and designs may become colored again, causing a so-called recoloring phenomenon.

However, in the present invention, since viscous water-soluble cobalt thiocyanate is used which has excellent compatibility with decoloring materials such as water-impregnated paper, cloth, and sponge, characters and designs after transfer are When the cobalt thiocyanate is brought into contact with the color erasing agent to erase the color, a dissociation reaction (erasing reaction) occurs easily, and the dissociated product or undissociated cobalt thiocyanate immediately diffuses into the color erasing agent. Because it is absorbed,
It is possible to suppress the recoloring phenomenon that sometimes occurs after these letters and designs are erased with water.

In addition, since the present invention does not contain water-insoluble components such as wax, cobalt thiocyanate is not mixed into or retained in these waxes, so most of the cobalt thiocyanate is mixed with water during decolorization. It is diluted upon contact, and as a result, its decoloring effect is enhanced, and it also has the advantage that solid content such as wax does not remain in the decolorized trace.

The copying material of the present invention is suitable as a copying material for drafting in fields such as sewing, embroidery, and lettering.

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

Example 1 15 g of cobalt thiocyanate was dissolved in 80 c.c. of water, and polyethylene glycol (molecular weight 200) was added to this.
25g was added and dissolved. Additionally, glycerin
40g was added to create a mixed solution. This solution took on a blue color. A filter paper was impregnated with this solution and the surface was dried. Layer cloth or paper under this impregnated paper,
When drawing lines were drawn on the impregnated paper using an iron brush, the corresponding blue drawing lines were transferred onto the cloth and paper. In order to erase the blue lines on this cloth or paper, another paper or cloth was impregnated with a small amount of water, and when the lines were wiped with this, the lines were immediately erased.

Example 2 20 g of nickel thiocyanate and 15 g of cobalt chloride were each added to 100 c.c. of water and dissolved. Add polyethylene glycol (molecular weight 200) to this solution.
30g of glycerin was added thereto, and further 50g of glycerin was added thereto to create a mixed solution. This solution took on a blue color.

A filter paper was impregnated with this solution and the surface was dried. Cloth or paper was placed under the impregnated paper, and when drawing lines were drawn on the impregnated paper using a ballpoint pen, the corresponding blue drawing lines were transferred onto the cloth and paper. In order to erase the blue lines on this cloth or paper, another paper or cloth was impregnated with a small amount of water, and when the lines were wiped with this, the lines were immediately erased.

Claims (1)

[Claims] 1 Contains cobalt thiocyanate as a coloring agent and a polyhydric alcohol as a color deepening agent and/or drying prevention agent, and the content of the polyhydric alcohol is 15
A copying material made by impregnating and retaining a viscous aqueous solution of ~60% by weight in a liquid-absorbing support, in which copied characters and designs can be erased with water. 2 The content of a coloring agent consisting of nickel thiocyanate and cobalt chloride, and a polyhydric alcohol as a color deepening agent and/or drying prevention agent is 15 to 60% by weight.
A copying material made by impregnating and retaining a viscous aqueous solution in a liquid-absorbing support, from which copied characters and designs can be erased with water.